如何使用 WCF DataContracts 自动反序列化 Yahoo GeoPlanet REST XML

发布于 2024-12-13 14:56:30 字数 2632 浏览 1 评论 0原文

我是 WCF 新手。我能够成功地为 GeoNames 服务创建一个客户端,但现在我尝试为 Yahoo GeoPlanet 做同样的事情,我似乎无法将 XML 反序列化为我的 DataContract 类型。这样做的正确方法是什么?以下是我正在处理的内容:

示例 REST 响应:

<places xmlns="http://where.yahooapis.com/v1/schema.rng" 
    xmlns:yahoo="http://www.yahooapis.com/v1/base.rng" 
    yahoo:start="0" yahoo:count="247" yahoo:total="247">
    <place yahoo:uri="http://where.yahooapis.com/v1/place/23424966" 
        xml:lang="en-US">
        <woeid>23424966</woeid>
        <placeTypeName code="12">Country</placeTypeName>
        <name>Sao Tome and Principe</name>
    </place>
    <place yahoo:uri="http://where.yahooapis.com/v1/place/23424824" 
        xml:lang="en-US">
        <woeid>23424824</woeid>
        <placeTypeName code="12">Country</placeTypeName>
        <name>Ghana</name>
    </place>
    ...
</places>

合约接口和合约接口客户端:

[ServiceContract]
public interface IConsumeGeoPlanet
{
    [OperationContract]
    [WebGet(
        UriTemplate = "countries?appid={appId}",
        ResponseFormat = WebMessageFormat.Xml,
        BodyStyle = WebMessageBodyStyle.Bare
    )]
    GeoPlanetResults<GeoPlanetPlace> Countries(string appId);
}

public sealed class GeoPlanetConsumer : ClientBase<IConsumeGeoPlanet>
{
    public GeoPlanetResults<GeoPlanetPlace> Countries(string appId)
    {
        return Channel.Countries(appId);
    }
}

反序列化类型:

[DataContract(Name = "places", 
    Namespace = "http://where.yahooapis.com/v1/schema.rng")]
public sealed class GeoPlanetResults<T> : IEnumerable<T>
{
    public List<T> Items { get; set; }

    public IEnumerator<T> GetEnumerator()
    {
        return Items.GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }
}


[DataContract]
public class GeoPlanetPlace
{
    [DataMember(Name = "woeid")]
    public int WoeId { get; set; }

    [DataMember(Name = "placeTypeName")]
    public string Type { get; set; }

    [DataMember(Name = "name")]
    public string Name { get; set; }

}

我知道这是错误的。在我的 geonames 客户端中,我的 GeoNamesResults 类有一个没有属性的 [DataContract] 属性,以及 上的 [DataMember(Name = "geonames")] 属性Items 属性。但这对 GeoPlanet 不起作用,我不断收到反序列化异常。我可以让 Countries(appId) 方法无异常地执行的唯一方法是将名称和命名空间放入 DataContract 属性中。但是,当我这样做时,我不知道如何将结果反序列化到 Items 集合中(它为空)。

我应该怎么办?

I am new to WCF. I was able to successfully create a client for the GeoNames service, but now that I am trying to do the same for Yahoo GeoPlanet, I can't seem to get the XML to deserialize into my DataContract types. What is the right way to do this? Here is what I am working with:

Sample REST response:

<places xmlns="http://where.yahooapis.com/v1/schema.rng" 
    xmlns:yahoo="http://www.yahooapis.com/v1/base.rng" 
    yahoo:start="0" yahoo:count="247" yahoo:total="247">
    <place yahoo:uri="http://where.yahooapis.com/v1/place/23424966" 
        xml:lang="en-US">
        <woeid>23424966</woeid>
        <placeTypeName code="12">Country</placeTypeName>
        <name>Sao Tome and Principe</name>
    </place>
    <place yahoo:uri="http://where.yahooapis.com/v1/place/23424824" 
        xml:lang="en-US">
        <woeid>23424824</woeid>
        <placeTypeName code="12">Country</placeTypeName>
        <name>Ghana</name>
    </place>
    ...
</places>

Contract Interface & Client:

[ServiceContract]
public interface IConsumeGeoPlanet
{
    [OperationContract]
    [WebGet(
        UriTemplate = "countries?appid={appId}",
        ResponseFormat = WebMessageFormat.Xml,
        BodyStyle = WebMessageBodyStyle.Bare
    )]
    GeoPlanetResults<GeoPlanetPlace> Countries(string appId);
}

public sealed class GeoPlanetConsumer : ClientBase<IConsumeGeoPlanet>
{
    public GeoPlanetResults<GeoPlanetPlace> Countries(string appId)
    {
        return Channel.Countries(appId);
    }
}

Deserialization Types:

[DataContract(Name = "places", 
    Namespace = "http://where.yahooapis.com/v1/schema.rng")]
public sealed class GeoPlanetResults<T> : IEnumerable<T>
{
    public List<T> Items { get; set; }

    public IEnumerator<T> GetEnumerator()
    {
        return Items.GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }
}


[DataContract]
public class GeoPlanetPlace
{
    [DataMember(Name = "woeid")]
    public int WoeId { get; set; }

    [DataMember(Name = "placeTypeName")]
    public string Type { get; set; }

    [DataMember(Name = "name")]
    public string Name { get; set; }

}

I know this is wrong. In my geonames client, my GeoNamesResults class has a [DataContract] attribute with no properties, and a [DataMember(Name = "geonames")] attribute on the Items property. This doesn't work for GeoPlanet though, I kept getting deserialization exceptions. The only way I could get the Countries(appId) method to execute without exceptions was by putting the Name and Namespace in the DataContract attribute. However when I do this, I have no idea how to get the results deserialized into the Items collection (it is null).

What should I do?

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评论(1

儭儭莪哋寶赑 2024-12-20 14:56:30

DataContractSerializer 不支持完整的 XML 规范,仅支持其中的一个子集。它不支持的是属性,这些属性在您展示的示例响应中广泛使用。在这种情况下,您需要使用 XmlSerializer,并相应地定义类型(使用 System.Xml.Serialization 中的属性,而不是 >系统.运行时.序列化)。下面的代码显示了如何检索您发布的示例 XML。

public class StackOverflow_8022154
{
    const string XML = @"<places xmlns=""http://where.yahooapis.com/v1/schema.rng""  
    xmlns:yahoo=""http://www.yahooapis.com/v1/base.rng""  
    yahoo:start=""0"" yahoo:count=""247"" yahoo:total=""247""> 
    <place yahoo:uri=""http://where.yahooapis.com/v1/place/23424966""  
        xml:lang=""en-US""> 
        <woeid>23424966</woeid> 
        <placeTypeName code=""12"">Country</placeTypeName> 
        <name>Sao Tome and Principe</name> 
    </place> 
    <place yahoo:uri=""http://where.yahooapis.com/v1/place/23424824""  
        xml:lang=""en-US""> 
        <woeid>23424824</woeid> 
        <placeTypeName code=""12"">Country</placeTypeName> 
        <name>Ghana</name> 
    </place> 
</places>";

    const string ElementsNamespace = "http://where.yahooapis.com/v1/schema.rng";
    const string YahooNamespace = "http://www.yahooapis.com/v1/base.rng";
    const string XmlNamespace = "http://www.w3.org/XML/1998/namespace";

    [XmlType(Namespace = ElementsNamespace, TypeName = "places")]
    [XmlRoot(ElementName = "places", Namespace = ElementsNamespace)]
    public class Places
    {
        [XmlAttribute(AttributeName = "start", Namespace = YahooNamespace)]
        public int Start { get; set; }
        [XmlAttribute(AttributeName = "count", Namespace = YahooNamespace)]
        public int Count;
        [XmlAttribute(AttributeName = "total", Namespace = YahooNamespace)]
        public int Total;
        [XmlElement(ElementName = "place", Namespace = ElementsNamespace)]
        public List<Place> AllPlaces { get; set; }

        public override string ToString()
        {
            StringBuilder sb = new StringBuilder();
            sb.AppendFormat("Places[start={0},count={1},total={2}]:", this.Start, this.Count, this.Total);
            sb.AppendLine();
            foreach (var place in this.AllPlaces)
            {
                sb.AppendLine("   " + place.ToString());
            }

            return sb.ToString();
        }
    }
    [XmlType(TypeName = "place", Namespace = ElementsNamespace)]
    public class Place
    {
        [XmlAttribute(AttributeName = "uri", Namespace = YahooNamespace)]
        public string Uri { get; set; }
        [XmlAttribute(AttributeName = "lang", Namespace = XmlNamespace)]
        public string Lang { get; set; }
        [XmlElement(ElementName = "woeid")]
        public string Woeid { get; set; }
        [XmlElement(ElementName = "placeTypeName")]
        public PlaceTypeName PlaceTypeName;
        [XmlElement(ElementName = "name")]
        public string Name { get; set; }

        public override string ToString()
        {
            return string.Format("Place[Uri={0},Lang={1},Woeid={2},PlaceTypeName={3},Name={4}]",
                this.Uri, this.Lang, this.Woeid, this.PlaceTypeName, this.Name);
        }
    }
    [XmlType(TypeName = "placeTypeName", Namespace = ElementsNamespace)]
    public class PlaceTypeName
    {
        [XmlAttribute(AttributeName = "code")]
        public string Code { get; set; }
        [XmlText]
        public string Value { get; set; }

        public override string ToString()
        {
            return string.Format("TypeName[Code={0},Value={1}]", this.Code, this.Value);
        }
    }
    [ServiceContract]
    public interface IConsumeGeoPlanet
    {
        [OperationContract]
        [WebGet(
            UriTemplate = "countries?appid={appId}",
            ResponseFormat = WebMessageFormat.Xml,
            BodyStyle = WebMessageBodyStyle.Bare
        )]
        [XmlSerializerFormat]
        Places Countries(string appId);
    }

    public sealed class GeoPlanetConsumer : ClientBase<IConsumeGeoPlanet>
    {
        public GeoPlanetConsumer(string address)
            : base(new WebHttpBinding(), new EndpointAddress(address))
        {
            this.Endpoint.Behaviors.Add(new WebHttpBehavior());
        }

        public Places Countries(string appId)
        {
            return Channel.Countries(appId);
        }
    }

    [ServiceContract]
    public class SimulatedYahooService
    {
        [WebGet(UriTemplate = "*")]
        public Stream GetData()
        {
            WebOperationContext.Current.OutgoingResponse.ContentType = "text/xml";
            return new MemoryStream(Encoding.UTF8.GetBytes(XML));
        }
    }

    public static void Test()
    {
        Console.WriteLine("First a simpler test with serialization only.");
        XmlSerializer xs = new XmlSerializer(typeof(Places));
        MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(XML));
        object o = xs.Deserialize(ms);
        Console.WriteLine(o);

        Console.WriteLine();
        Console.WriteLine("Now in a real service");
        Console.WriteLine();
        string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
        WebServiceHost host = new WebServiceHost(typeof(SimulatedYahooService), new Uri(baseAddress));
        host.Open();
        Console.WriteLine("Host opened");

        GeoPlanetConsumer consumer = new GeoPlanetConsumer(baseAddress);
        Places places = consumer.Countries("abcdef");
        Console.WriteLine(places);
    }
}

The DataContractSerializer doesn't support the full XML specification, only a subset of it. On thing it doesn't support is attributes, which are used extensively in the sample response you showed. In this case, you'll need to use the XmlSerializer, and define the types accordingly (using the attributes in System.Xml.Serialization, instead of the ones on System.Runtime.Serialization). The code below shows how to retrieve the sample XML you posted.

public class StackOverflow_8022154
{
    const string XML = @"<places xmlns=""http://where.yahooapis.com/v1/schema.rng""  
    xmlns:yahoo=""http://www.yahooapis.com/v1/base.rng""  
    yahoo:start=""0"" yahoo:count=""247"" yahoo:total=""247""> 
    <place yahoo:uri=""http://where.yahooapis.com/v1/place/23424966""  
        xml:lang=""en-US""> 
        <woeid>23424966</woeid> 
        <placeTypeName code=""12"">Country</placeTypeName> 
        <name>Sao Tome and Principe</name> 
    </place> 
    <place yahoo:uri=""http://where.yahooapis.com/v1/place/23424824""  
        xml:lang=""en-US""> 
        <woeid>23424824</woeid> 
        <placeTypeName code=""12"">Country</placeTypeName> 
        <name>Ghana</name> 
    </place> 
</places>";

    const string ElementsNamespace = "http://where.yahooapis.com/v1/schema.rng";
    const string YahooNamespace = "http://www.yahooapis.com/v1/base.rng";
    const string XmlNamespace = "http://www.w3.org/XML/1998/namespace";

    [XmlType(Namespace = ElementsNamespace, TypeName = "places")]
    [XmlRoot(ElementName = "places", Namespace = ElementsNamespace)]
    public class Places
    {
        [XmlAttribute(AttributeName = "start", Namespace = YahooNamespace)]
        public int Start { get; set; }
        [XmlAttribute(AttributeName = "count", Namespace = YahooNamespace)]
        public int Count;
        [XmlAttribute(AttributeName = "total", Namespace = YahooNamespace)]
        public int Total;
        [XmlElement(ElementName = "place", Namespace = ElementsNamespace)]
        public List<Place> AllPlaces { get; set; }

        public override string ToString()
        {
            StringBuilder sb = new StringBuilder();
            sb.AppendFormat("Places[start={0},count={1},total={2}]:", this.Start, this.Count, this.Total);
            sb.AppendLine();
            foreach (var place in this.AllPlaces)
            {
                sb.AppendLine("   " + place.ToString());
            }

            return sb.ToString();
        }
    }
    [XmlType(TypeName = "place", Namespace = ElementsNamespace)]
    public class Place
    {
        [XmlAttribute(AttributeName = "uri", Namespace = YahooNamespace)]
        public string Uri { get; set; }
        [XmlAttribute(AttributeName = "lang", Namespace = XmlNamespace)]
        public string Lang { get; set; }
        [XmlElement(ElementName = "woeid")]
        public string Woeid { get; set; }
        [XmlElement(ElementName = "placeTypeName")]
        public PlaceTypeName PlaceTypeName;
        [XmlElement(ElementName = "name")]
        public string Name { get; set; }

        public override string ToString()
        {
            return string.Format("Place[Uri={0},Lang={1},Woeid={2},PlaceTypeName={3},Name={4}]",
                this.Uri, this.Lang, this.Woeid, this.PlaceTypeName, this.Name);
        }
    }
    [XmlType(TypeName = "placeTypeName", Namespace = ElementsNamespace)]
    public class PlaceTypeName
    {
        [XmlAttribute(AttributeName = "code")]
        public string Code { get; set; }
        [XmlText]
        public string Value { get; set; }

        public override string ToString()
        {
            return string.Format("TypeName[Code={0},Value={1}]", this.Code, this.Value);
        }
    }
    [ServiceContract]
    public interface IConsumeGeoPlanet
    {
        [OperationContract]
        [WebGet(
            UriTemplate = "countries?appid={appId}",
            ResponseFormat = WebMessageFormat.Xml,
            BodyStyle = WebMessageBodyStyle.Bare
        )]
        [XmlSerializerFormat]
        Places Countries(string appId);
    }

    public sealed class GeoPlanetConsumer : ClientBase<IConsumeGeoPlanet>
    {
        public GeoPlanetConsumer(string address)
            : base(new WebHttpBinding(), new EndpointAddress(address))
        {
            this.Endpoint.Behaviors.Add(new WebHttpBehavior());
        }

        public Places Countries(string appId)
        {
            return Channel.Countries(appId);
        }
    }

    [ServiceContract]
    public class SimulatedYahooService
    {
        [WebGet(UriTemplate = "*")]
        public Stream GetData()
        {
            WebOperationContext.Current.OutgoingResponse.ContentType = "text/xml";
            return new MemoryStream(Encoding.UTF8.GetBytes(XML));
        }
    }

    public static void Test()
    {
        Console.WriteLine("First a simpler test with serialization only.");
        XmlSerializer xs = new XmlSerializer(typeof(Places));
        MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(XML));
        object o = xs.Deserialize(ms);
        Console.WriteLine(o);

        Console.WriteLine();
        Console.WriteLine("Now in a real service");
        Console.WriteLine();
        string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
        WebServiceHost host = new WebServiceHost(typeof(SimulatedYahooService), new Uri(baseAddress));
        host.Open();
        Console.WriteLine("Host opened");

        GeoPlanetConsumer consumer = new GeoPlanetConsumer(baseAddress);
        Places places = consumer.Countries("abcdef");
        Console.WriteLine(places);
    }
}
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